Institute of Vegetable and Floriculture Science, National Agriculture and Food Research Organization (NARO), Fujimoto 2-1, Tsukuba, Ibaraki, 305-0852, Japan.
Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, 606-8522, Japan.
Planta. 2020 Apr 24;251(5):101. doi: 10.1007/s00425-020-03393-3.
Simultaneous knockdown or knockout of Torenia fournieri PLENA (TfPLE) and FALINELLI (TfFAR) genes with RNAi or genome-editing technologies generated a multi-petal phenotype in torenia. The MADS-box gene AGAMOUS (AG) is well known to play important roles in the development of stamens and carpels in Arabidopsis. Mutations in AG cause the morphological transformation of stamens and carpels into petaloid organs. In contrast, torenia (Torenia fournieri Lind.) has two types of class-C MADS-box genes, PLENA (PLE) and FALINELLI (FAR); however, their functions were previously undetermined. To examine the function of TfPLE and TfFAR in torenia, we used RNAi to knockdown expression of these two genes. TfPLE and TfFAR double-knockdown transgenic torenia plants had morphologically altered stamens and carpels that developed into petaloid organs. TfPLE knockdown transgenic plants also exhibited morphological transformations that included shortened styles, enlarged ovaries, and absent stigmata. Furthermore, simultaneous disruption of TfPLE and TfFAR genes by CRISPR/Cas9-mediated genome editing also resulted in the conversion of stamens and carpels into petaloid organs as was observed in the double-knockdown transgenic plants mediated by RNAi. In addition, the carpels of one TfPLE knockout mutant had the same morphological abnormalities as TfPLE knockdown transgenic plants. TfFAR knockdown genome-edited mutants had no morphological changes in their floral organs. These results clearly show that TfPLE and TfFAR cooperatively play important roles in the development of stamens and carpels. Simultaneous disruption of TfPLE and TfFAR functions caused a multi-petal phenotype, which is expected to be a highly valuable commercial floral trait in horticultural flowers.
利用 RNAi 或基因组编辑技术同时敲低或敲除 Torenia fournieri PLENA（TfPLE）和 FALINELLI（TfFAR）基因，可在 Torenia 中产生多瓣花表型。MADS 框基因 AGAMOUS（AG）在拟南芥雄蕊和心皮发育中发挥重要作用。AG 突变导致雄蕊和心皮形态转化为花瓣状器官。相比之下，Torenia（Torenia fournieri Lind.）有两种类型的 C 类 MADS 框基因，PLENA（PLE）和 FALINELLI（FAR）；然而，它们的功能以前尚未确定。为了研究 TfPLE 和 TfFAR 在 Torenia 中的功能，我们使用 RNAi 敲低这两个基因的表达。TfPLE 和 TfFAR 双敲低转基因 Torenia 植株的雄蕊和心皮形态发生改变，发育成花瓣状器官。TfPLE 敲低转基因植株还表现出形态变化，包括花柱缩短、子房增大和柱头缺失。此外，CRISPR/Cas9 介导的基因组编辑同时破坏 TfPLE 和 TfFAR 基因也导致雄蕊和心皮转化为花瓣状器官，这与 RNAi 介导的双敲低转基因植物观察到的结果一致。此外，TfPLE 敲除突变体的一个心皮具有与 TfPLE 敲低转基因植物相同的形态异常。TfFAR 敲低基因组编辑突变体的花器官没有形态变化。这些结果清楚地表明，TfPLE 和 TfFAR 协同作用在雄蕊和心皮的发育中发挥重要作用。TfPLE 和 TfFAR 功能的同时破坏导致多瓣花表型，这有望成为园艺花卉中极具商业价值的花卉特征。
